Calendar: wrong header of year view

[ilhan007]

Describe the feature request
Calendar: we would like to display "year range" label within the header, whenever you the user enters the Year view.

Current state

1. Go to https://sap.github.io/ui5-webcomponents/master/playground/components/Calendar/
2. Open 1st Calendar
3. Press over the year button
4. Observe how the a "month" button is displayed in the header, instead of year range

Reference SAPUI5

[ilhan007]

Tsani suggested to resolve this is backlog item, that's why it's in the planning section.